re: Czechoslovakia 1945 liberation local overprint. Info needed.
I do not have the resources at hand right now, but first impression: fantasy, fake, or whatever you want to call it. At least they are not genuine.
The type of overprint alone would be reason for suspicion: if you want to create provisional stamps, you would expect crude black overprints, not fancy 3 colour rasterized printing.
re: Czechoslovakia 1945 liberation local overprint. Info needed.
Definitely not my area, but I assume these are not genuine. Google Images is always a good place to start, and I can't find anything remotely similar. Most are, as Jansimon says, quite crude.